On 25.09.2018 12:08, Miklos Szeredi wrote: > On Tue, Sep 11, 2018 at 12:12 PM, Kirill Tkhai <ktkhai@xxxxxxxxxxxxx> wrote: >> We noticed the performance bottle neck in FUSE running our >> Virtuozzo storage over rdma. On some types of workload >> we observe 20% of times pent in request_find() in profiler. >> This function is iterating over long requests list, and it >> scales bad. >> >> The patch introduces hash table to reduce the number >> of iterations, we do in this function. Hash generating >> algorithm is taken from hash_add() function, while >> 512 lines table is used to store pending requests. >> This fixes problem and improves the performance. > > Pushed to fuse.git#for-next with a number of small changes. E.g. I Thanks! > reduced the number of cachlines to 256 to make the hashtable size just > 4k. Was there a scientific reason for choosing 512 as the optimal > number of cache lines? I just tried to choose a size, which is not small for all of potential users. But, it looks like 256 should be also enough. So, there was no hidden mathematics... Kirill
